Lattice Always-On Sensor Solutions for Context-Aware Mobile Devices

The folks at Lattice Semiconductor have just announced a new family of iCE40 FPGAs that slash power consumption by 100x and are so small they can fit almost anywhere to make always-on, context-aware sensor integration a reality.

One of the world's biggest industries at the moment is handsets and smartphones. These have evolved some amazing capabilities to the extent that they are now molding our lives and affecting how we relate to family, friends, and colleagues.

As amazing as today's devices are, however, we are still only poised at the beginning of a new era of intelligent, context-aware devices that take full advantage of micro-miniature sensor technologies.

If we consider a cellphone from a relatively few years ago, it may have included a simply proximity sensor that would blank out the screen when you brought the phone to your ear, thereby saving power. Over time, more and more sensors have been added, including things like ambient light sensors, magnetometers, multi-axis accelerometers, multi-axis gyroscopes, and so forth.

Now, the developers of devices like smartphones are working on making them even smarter. In particular, they wish to make these devices more aware of their surroundings and also aware of their user's context. Where are you (in the street, in a building, on a plane)? What are you doing (sitting, walking, running, riding a bike, leaning against a wall)? What's happening around you (it's hot, it's sunny, it's windy, it's raining, the ground is shaking... eeekkk!)?

The reason we need always-on, context-aware devices is so that they can better meet our needs. One problem is that when something is always on, it's always drawing power. The worst culprits when it comes to burning power are microcontrollers and application processors. Another problem is that devices like smartphones are now so jam-packed with sensors and displays and application processors that they are extremely space-constrained, so any solution that supports the always-on, context-aware processing of data from myriad sensors has to be incredibly tiny.

All of which explains why the folks at Lattice Semiconductor are so excited with their new iCE40 FPGAs, which are based on the ultra-low-power technology they acquired from SiliconBlue.

In addition to offering the world's smallest single-chip sensor solutions, these devices also consume only a miniscule amount of always-on power (less than 1 milliwatt) while still providing near-zero latency for accurate context awareness.

During my briefing on all of this, the folks at Lattice gave a rather powerful demonstration featuring an iCE40LM sensor daughter card as illustrated below. In addition to the ultra-low-power iCE40LM FPGA itself, this card boasts a cornucopia of sensors, including an accelerometer, a gyroscope, a compass, a barometer, a proximity detector, an RGB ambient light sensor, a humidity sensor, a temperature sensor, and an infrared transmitter and receiver.

In the image below we see the test setup, in which the iCE40LM sensor daughter card is plugged in to a Snapdragon board and display, featuring a QualComm 8060 applications processor along with a smartphone evaluation and software development kit.

The example application used in this demonstration was to implement a pedometer. In this case, the iCE40LM monitors the accelerometer and pre-processes the data and stores the data while the main (power-guzzling) application processor snoozes away. The iCE40LM only wakes the application processor when the occasion demands. The image below shows the daughter card carrying the iCE40LM being swung back and forth to replicate someone walking. The multimeter is displaying the current being consumed by the iCE40LM, which -- in this case -- is less than 3/4 of 1mA.

These new ultra-low-power FPGAs are already in production and are available through Lattice’s distribution partners, with prices starting at under US $1 dollar in high volume quantities. If you are interested in learning more, just click here to bounce over to the Lattice website.

Being an FPGA, it is really tiny!! It is ideal for the applications for which it is made: consumes extremely low power and "... only wakes the application processor when the occasion demands".

What about storing the configuration? Does it need a FLASH or some memory to store the configuration and picks it during power-up like the traditional FPGAs? Why there was an FPGA needed in this size, where the functions it might do for sensing application, could be done by a tiny CPLD?

Yep app processors need to stay off as much as possible. We will need a multi-level 'cache' equivalent for sensor functions. Need to have levels of processing available for different functions each at 1/10 the power of the previous. The lattice parts are one piece of the puzzle.

It seems that many programmable logic devices are starting to enable always-on sensor solutions. This is a need for a plethora of new mobile applications -- I just wonder if SoC switching time rates from low power modes to active run will be able to take advantage of this capabilities without drawing the battery charge saved by sensor frontend!!